1. College of Grassland and Environment Sciences, Xinjiang Agricultural University, Urumqi, Xinjiang, China
2. Institute of Grassland, Xinjiang Academy of Animal Science, Urumqi, Xinjiang, China
3. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
4. School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu, China